Depending on the Transmission Mode about 15MBit can get transmitted per Transponder (Frequency). This is enough for one HDTV channel or 4-5 Standard Definition TV channels. Multiple channels can be organized in Bouquets (a bunch of services by a particular Service Provider).

Tip

Crazy as it may sound, if you find that video and audio sometimes freeze (and there are no error messages in /var/log/messages), your aerial signal may be too weak. A signal booster made a significant difference in my setup (Hauppauge Nova-T (Conexant) + Avermedia 771 DVB-T, 2.6.13-rc7 + dvb kernel patches from CVS)